Full-Duplex Self-Interference Cancellation Method and Apparatus

1. A non-transitory computer-readable storage medium storing instructions that, when the instructions are run on a computer, cause the computer to perform the following operations: time reversal-filtering a sending signal and feeding a time reversal-filtered sending signal into a first self-interference reconstruction module, to obtain a first-level self-interference reconstruction signal; directly feeding the sending signal into a second self-interference reconstruction module, to obtain a second-level self-interference reconstruction signal; and performing, based on the first-level self-interference reconstruction signal and the second-level self-interference reconstruction signal, self-interference cancellation on a radio frequency signal received by a receive antenna, wherein the second self-interference reconstruction module comprises a fixed delay line, a variable attenuator, and a phase shifter, two ends of the variable attenuator are respectively connected to the fixed delay line and the phase shifter, and the sending signal is directly fed into the fixed delay line and sequentially passes through the variable attenuator and the phase shifter, to obtain the second-level self-interference reconstruction signal.

2. The non-transitory computer-readable storage medium according to claim 1, wherein the phase shifter is a variable phase shifter.

3. The non-transitory computer-readable storage medium according to claim 1, wherein the phase shifter is a fixed phase shifter.

4. The non-transitory computer-readable storage medium according to claim 1, wherein the sending signal is time reversal-filtered in the following manner: γ(t)=x(t)⊗(K·h*(−t)), wherein γ(t) indicates the time reversal-filtered sending signal, x(t) indicates the sending signal, h*(−t) indicates time reversal filtering on x(t), h*(−t) indicates a conjugate of h(−t), h(−t) indicates time reversal of h(t), h(t) indicates an impulse response to a residual self-interference channel obtained after the first-level self-interference reconstruction signal is canceled from the radio frequency signal received by the receive antenna, and K is a normalized coefficient.

5. The non-transitory computer-readable storage medium according to claim 1, wherein a transmit antenna and the receive antenna are not independent, the first self-interference reconstruction module comprises: a first reconstruction branch configured to reconstruct a self-interference component that enters the receive antenna through reflection, a second reconstruction branch configured to reconstruct a self-interference component that enters the receive antenna through leakage, and a combiner configured to combine reconstruction signals of the first and second reconstruction branches; and the time reversal-filtered sending signal is divided into two signals using a power divider, the two signals respectively pass through the first reconstruction branch and the second reconstruction branch to obtain the first-level self-interference reconstruction signals and the second-level self-interference reconstruction signal, and the first-level self-interference reconstruction signal and the second-level self-interference reconstruction signal are combined using the combiner.

6. The non-transitory computer-readable storage medium according to claim 5, wherein the first reconstruction branch comprises a fixed delay line, a fixed attenuator, and a fixed phase shifter, two ends of the fixed attenuator are respectively connected to the fixed delay line and the fixed phase shifter, and the time reversal-filtered sending signal is fed into the fixed delay line and sequentially passes through the fixed attenuator and the fixed phase shifter, to obtain the reconstruction signal of the first reconstruction branch.

7. The non-transitory computer-readable storage medium according to claim 5, wherein the second reconstruction branch comprises a fixed delay line, a fixed attenuator, and a fixed phase shifter, two ends of the fixed attenuator are respectively connected to the fixed delay line and the fixed phase shifter, and the time reversal-filtered sending signal is fed into the fixed delay line and sequentially passes through the fixed attenuator and the fixed phase shifter, to obtain the reconstruction signal of the second reconstruction branch.

8. The non-transitory computer-readable storage medium according to claim 1, wherein a transmit antenna and the receive antenna are independent, the first self-interference reconstruction module comprises a fixed delay line, a fixed attenuator, and a fixed phase shifter, two ends of the fixed attenuator are respectively connected to the fixed delay line and the fixed phase shifter, and the time reversal-filtered sending signal is fed into the fixed delay line and sequentially passes through the fixed attenuator and the fixed phase shifter, to obtain the first-level self-interference reconstruction signal.

9. A non-transitory computer-readable storage medium storing instructions that, when the instructions are run on a computer, cause the computer to perform the following operations: performing first-level self-interference cancellation on a sending signal in a half-duplex timeslot, to obtain a first residual self-interference signal; performing residual self-interference channel estimation based on the first residual self-interference signal, to obtain an impulse response to a first residual self-interference channel; time reversal-filtering the sending signal based on the impulse response to the first residual self-interference channel; performing first-level self-interference cancellation on a time reversal-filtered sending signal, to obtain a second residual self-interference signal; performing second-level self-interference cancellation on the second residual self-interference signal, to obtain a third residual self-interference signal; and performing residual self-interference channel estimation based on the third residual self-interference signal, to obtain an impulse response to a second residual self-interference channel, wherein the impulse response to the second residual self-interference channel is applied to digital interference cancellation in a full-duplex timeslot.

10. A full-duplex self-interference cancellation system, wherein the full-duplex self-interference cancellation system comprises: a first self-interference cancellation apparatus including a first time reversal filter, a second time reversal filter, a first self-interference reconstruction module, a second self-interference reconstruction module, and a first combiner; and a second self-interference cancellation apparatus including a third time reversal filter, a fourth time reversal filter, a third self-interference reconstruction module, a fourth self-interference reconstruction module, and a second combiner.

11. The full-duplex self-interference cancellation system according to claim 10, wherein the second time reversal filter is configured to time reversal-filter a first sending signal, the first time reversal filter is configured to time reversal-filter a time reversal-filtered first sending signal output by the second time reversal filter; the fourth time reversal filter is configured to time reversal-filter a second sending signal; the third time reversal filter is configured to time reversal-filter a time reversal-filtered second sending signal output by the fourth time reversal filter.